Tube for use in diagnostic and therapy control



Nov. 23, 1965 R. SCHWARZ, JR.. ETAL 3,219,421

TUBE FOR USE IN DIAGNOSTIC AND THERAPY CONTROL Original Filed March 20,1963 lNVENTORS ATTORNE United States Patent Office 3,219,421 PatentedNov. 23, 1965 3,219,421 TUBE FOR USE IN DIAGNOSTIC AND THERAPY CONTROLRobert Schwarz, Jr., Tenafly, and Helmut G. Tietje, Westwood, NJ.Continuation of application Ser. No. 266,587, Mar. 20, 1963. Thisapplication Jan. 18, 1965, Ser. No. 426,095 2 Claims. ((31. 23292) Thisapplication constitutes a continuation of application Serial No.266,587, filed March 20, 1963, which is a continuation-impart ofapplication Serial No. 188,357, filed April 18, 1962, both nowabandoned.

The present invention relates to an improved tube construction fordiagnostic and therapy control applications, and more particularly, to atube of this nature facilitating the expeditious identification of thetube contents.

In clinical as well as laboratory practice, samples of materials to betested are frequently placed in tubes, vials or similar vessels andreceptacles, In this connection, various controls and reagents aresimilarly contained as part of the diagnosis and particular therapyunder consideration. The particular tube contents may then be placedthrough at least one of a series of tests and may even have samplesthereof extracted or aspirated and mixed as part of the test procedure.Quite obviously, if the tubes are not properly identified, theircontents and the samples thereof may not be properly employed, therebyenhancing the possibility of obtaining erroneous test results. Theconsequences could be extremely confusing, if not damaging anddetrimental.

For example, the tubes may be utilized in prothrombin and coagulationtime determinations wherein standardized and stabilized chemicalreagents are placed in such tubes and heated to selected operatingtemperatures, approximately that of the normal human body. The quantityof reagent is ordinarily fixed for proper time determinations. Controlplasma of predetermined quantity, also in such tubes, is then dispensedin one of the tubes containing a reagent. A probe, either manually orautomatically operated, is then inserted and withdrawn from this tubefor purposes of sensing the initial clot formation. The same procedureis followed utilizing a controlled amount of patients plasma. Theprothrombin times are read and recorded. If the tubes and their contentsare not clearly identified, confusion is likely to ensue; and inaccurateresults are inevitable, particularly in view of the critical nature oftime in such investigations. This environment as well as application ofthe tube of this invention is disclosed in detail in application SerialNo. 188,934 filed April 18, 1962.

It is, therefore, a primary object of this invention to provide astructurally improved tube for use in diagnostic and therapeutic work,having means for receiving indicia readily viewable by the diagnosticianor clinical attendant.

The present invention contemplates essentially a tube of standardvolumetric capacity closed at one end and open at the other. A radialflange extends integrally from the open end of the tube and is soconstructed and arranged to provide a relatively enlarged surface area.This area is so conditioned to permit the reception of the desiredindicia. Under these circumstances, the tube and its ultimate contentsare most expeditiously identified; and their possible erroneous use andmisapplication of test samples of the tube contents effectivelyminimized, if not eliminated, In addition, tube dimensioning andmaterials for tube fabrication are selected to assure accurateprothrombin time determinations because of optimum volumetric controland heat transfer.

Other objects and advantages will become apparent from the followingdetailed description which is to be taken in connection with theaccompanying drawing illustrating a somewhat preferred embodiment of theinvention, in which:

FIG. 1 is a top perspective View of the tube embodying the teachings ofthe present invention shown associated with another identical tube bothof which are mounted in a heating block fragmentarily illustrated;

FIG. 2 is an enlarged top plan view thereof; and

FIG. 3 is a longitudinal sectional view taken along the line 33 of FIG.2.

In the drawings, a tube 10 of any desired volumetric capacity will beformed with the usual cylindrical side wall 12 having a bottom closedend 14 and opened upper end 16. In this connection, it has been founddesirable to provide the tube 10 with standard volumetric capacitieswhich, for example, may be in the nature of a few tenths of amilliliter. This size tube would have particular application toprothrombin and coagulation time determinations. The materials utilizedin fabricating the tube 10 may be any one of a number of resins orplastics possessing characteristics and properties desirable for theselected tube applications and uses. With this in mind, the tube 10 ispreferably of a disposable nature such that, after a particular singleuse, it may be discarded thereby eliminating the need for cleansing andsterilization. It should be understood, however, that materials lendingthemselves to permanent use and the various sterilization techniques arealso embraced by this invention. A successful and somewhat preferableapplication of this invention embraces those dimensions and materialsspecifically set forth below.

Since it is particularly important to incorporate conveniently locatedindicia receiving means, the tube 10 is formed with a flange 18extending radially outwardly from the open end 16. This flange isadvantageously enlarged to provide an elongated radial strip 20 havingan enlarged upper face 22. The desired indicia can be convenientlyplaced on this surface so that it can be readily viewed. Thus, the topface 22 may be defined by a pair of spaced and substantially parallelside edges 24 and 26 extending tangentially from the periphery 28 offlange 18. The terminal ends of the periphery edges 24 and 26 areconnected by an annular side edge 30 to provide the top of the tube 10with a somewhat symmetrical appearance. Under these circumstances, theupper face 22 of the strip 20 will provide suflicient area for thereception of the selected indicia.

In order to expedite the placement of indicia on the strip 20, a zone 32of the upper face may be treated either chemically or mechanically toprovide a roughened surface on which writing may be inscribed as, forexample, with an ordinary pencil or pen. On the other hand, the zone 32for writing may be the result of the molding process employed. It hasbeen found that satisfactory results are obtainable by providing zone 32with the desired properties and characteristics through frosting, sandblasting and the like techniques. In any event,

in order to provide a symmetrical and neat appearance, particularly whenviewing the strip 20 and its upper face 22, the zone 32 may be definedby a pair of spaced and parallel edges 34 and 36 extending tangentiallyfrom the inner face of the top end 16. The edge 30 of the strip 20 maydefine the remaining side of the zone 32.

Thus, in assuring accurate application of the tube and its contents tothe particular diagnostic and therapeutic determinations, the desiredindicia, which may be inscribed, marked or in any other discernablemedia readilyidentifiable, need only be placed or written on the upperface 22 of the strip 20. In this connection, an adhesively coated stripor tape can be applied to the upper face 22 and bear the desired data.Quite obviously, other data can be similarly placed or written from timeto time in lieu of or in addition to the original. Of importance is thefact that the strip does not detrimentally affect the handling of thetube 10, nor render it cumbersome in filling or removing any of the tubecontents. In fact, provisions for the strip 20 in accordance with thepresent invention eliminates marking of the body 12 of the tube 10 witheither written material or adhesively backed tape. Under suchcircumstances,

the tube contents would from time to time be hidden from view andcertainly not be clearly viewable through the entire length of the tube.Tape would also interfere with fit in heating block which wouldinterfere with heat transmission and might make insertion impossible ormight prevent seating which is required for automatic determination ofprothrombin time, for example.

In arriving at the dimensioning of the tube 10, the following criteriashould be considered:

(a) The length of strip 20 should be sufliciently long to permit manualgripping thereof as well as adequate room for labelling; and the stripshould not be unduly lengthened thereby resulting in occlusion of theopenings of adjacent tubes or prevention of seating of the subject tubeor prevention of insertion of adjacent tubes.

(b) The thickness of the side wall 12 should be selected to avoidproviding undesirable flexibility; and the thickness should not beincreased beyond that point at which heat conduction therethrough willbe decreasedsignificantly thereby resulting in inconveniently longsolution warm-up times.

(c) The outer diameter of the tube side wall 12, together with that ofthe bottom closed end 14, should be selected such that it is not toolarge thereby making proper seating of the tube in the well of a heatingblock, for example, extremely difiicult if not impossible; and if thisouter diameter is too small, particularly in relation to this well,proper heat transmission into the tube contents will be detrimentallyaffected.

(d) The inner diameter of the tube side wall 12 and bottom closed end14, if too small, will raise liquid level to an extent whereby a clotwill be registered by a coagulation timer, of the type disclosed inapplication Serial No. 188,934 filed April 18, 1962, through the levelof the liquid even without formation of a clot; and if this dimension istoo large, the liquid level in the tube will be lowered to a point atwhich the clot will not be picked up and sensed. Value of the internaldiameter specifically disclosed below is important for the followingreasons:

(1) that if narrower, the sensitivity to pipetting error will beexcessive and there will be an increase in the criticality of thedistance between the upper surface of the liquid in the tube and thesensing probe of the above mentioned coagulation timer; and

(2) that if wider, the upper surface area of the tube contents will beincreased to the extent that evaporation and heat loss may give rise toproblems afifecting accuracy of prothrombin times; and the portion ofthe vertical section of the liquid swept through by the sensing probewill be decreased to the extent that the factor of missing a clot willbe introduced.

(e) The outer surface of the side wall 12 and closed bottom end 14should be sufficiently smooth to insure adequate heat transmission fromwell to tube; and the inner surface should 'be smooth to insure that thetube contents are adequately mixed.

A successful application of the tube of this invention embraced thefollowing dimensioning.

Tube bottom end 14:

Inner radius 1943.001"

Outer radius 2221.001 Tube side wall 12:

Thickness .028 .002

Taper (outwardly to open end) 130'il0' Tube height .750i.0l0" Strip 20:

Radius .518"

Width .625

A preferred material from which the tube of this invention is fabricatedbecause of its superior dimensional suitability and optimum heattransfer characteristics is high density polyethylene. In thisconnection, this material provided for heat transmission through thetube from the well to the tube contents in a minimum period of time. Inaddition, tube shrinkage was significantly minimized, if not eliminated,and acceptable matching or meeting relationship between tube and wellwas attained in substantially all instances. Consequently, errors inprothrombin time determinations were reduced.

It should, therefore, be understood that the aforenoted objects andadvantages, among others, are most effectively attained. Although asingle somewhat preferred embodiment of this invention has beendisclosed and described in detail herein, the invention is not in anysense limited thereby, and its scope is to be determined by that of theappended claims.

We claim:

1. A disposable tube having ability for obtaining optimum liquid leveland heat transfer characteristics and being of standard volumetriccapacity for containing a liquid sample in the order of tenths of amilliliter for use in diagnostic and therapy control in prothrombin timedeterminations made in a coagulation timer which are carried out at bodytemperatures within said tube, said tube being formed of moldedsynthetic resin suitable for coagulation tests and having suitable heattransfer characteristics, said tube having an open top end and a closedbottom end, the tube having a circular cross section substantiallythroughout its length, the interior and exterior surfaces of the tubebeing substantially smooth, the length of said tube being larger thanits internal diameter and the closed bottom of said tube beinghemispherical in configuration, the open end of said tube being providedwith a flange extending radially outwardly of the tube, said flangehaving a substantially semi-circular peripheral edge, a strip projectingradially from the tube open end in the form of an integral extension forpermitting manual holding of the tube, said strip having a pair ofspaced side edges extending substantially tangentially from theperipheral edge, said strip having 29. length and width which cooperatetogether in providing a surface area sufficient for reception ofselected indicia, the resin and thickness being selected such that thetube is provided with minimum flexibility and maintains its shape undertest conditions at approximately body temperatures and provides suitableheat conductivity during warmup of the liquid contents of the tube andduring the coagulation tests, the inner radius of the tube permittingvertical manipulation of a probe into and out of the liquid so as tosense a clot, the tube tapering outwardly from the closed end to theopen end, the tapering and the outer radius of the tube being selectedto provide op timum contact with the heat source.

2. The invention in accordance with claim 1 wherein the molded syntheticresin consists of high density polyethylene.

References Cited by the Examiner UNITED STATES PATENTS 2,346,261 4/1944Kamlet 23292 2,837,055 6/1958 Whitehead 16784.5 X

6 3,068,855 12/1962 Furlong 23-230 X 3,071,316 1/1963 Piemonte et a1.23-292 X 3,115,460 12/1963 McCormick 23292 X OTHER REFERENCES ModernLaboratory Appliances, Fisher Scientific Co. Catalog 59, pp. 104 and 195(1958), Fisher Scientific Co., New York, N.Y.

MORRIS O. WOLK, Primary Examiner.

1. A DISPOSABLE TUBE HAVING ABILITY FOR OBTAINING OPTIMUM LIQUID LEVELAND HEAT TRANSFER CHARACTERISTICS AND BEING OF STANDARD VOLUMETRICCAPACITY FOR CONTAINING A LIQUID SAMPLE IN THE ORDER OF TENTHS OF AMILLILITER FOR USE IN DIAGNOSTIC AND THERAPY CONTROL IN PROTHROMBIN TIMEDETERMINATIONS MADE IN A COAGULATION TIMER WHICH ARE CARRIED OUT AT BODYTEMPERATURES WITHIN SAID TUBE, SAID TUBE BEING FORMED OF MOLDEDSYNTHETIC RESIN SUITABLE FOR COAGULATION TESTS AND HAVING SUITABLE HEATTRANSFER CHARACTERISTICS, SAID TUBE HAVING AN OPEN TOP END AND A CLOSEDBOTTOM END, THE TUBE HAVING A CIRCULAR CROSS SECTION SUBSTANTIALLYTHROUGHOUT ITS LENGTH, THE INTERIOR AND EXTERIOR SURFACES OF THE TUBEBEING SUBSTANTIALLY SMOOTH, THE LENGTH OF SAID TUBE BEING LARGER THANITS INTERNAL DIAMETER AND THE CLOSED BOTTOM OF SAID TUBE BEINGHEMISPHERICAL IN CONFIGURATION, THE OPEN END OF SAID TUB E BEINGPROVIDED WITH A FLANGE EXTENDING RADIALLY OUTWARDLY OF THE TUBE, SAIDFLANGE HAVING A SUBSTANTIALLY SEMI-CIRCULAR PERIPHERAL EDGE, A STRIPPROJECTING RADIALLY FROM THE TUBE OPEN END IN THE FORM OF AN INTEGRALEXTENSION FOR PERMITTING MANUAL HOLDING OF THE TUBE, SAID STRIP HAVING APAIR OF SPACED SIDE EDGES EXTENDING SUBSTANTIALLY TANGENTIALLY FROM THEPERIPHERAL EDGE, SAID STRIP HAVING A LENGTH AND WIDTH WHICH COOOPERATETOGETHER IN PROVIDING A SURFACE AREA SUFFICIENT FOR RECEPTION OFSELECTED INDICIA, THE RESIN AND THICKNESS BEING SELECTED SUCH THAT THETUBE IS PROVIDED WITH MINIMUM FLEXIBILITY AND MAINTAINS ITS SHAPE UNDERTEST CONDITIONS AT APPROXIMATELY BODY TEMPERATURES AND PROVIDES SUITABLEHEAT CONDUCTIVITY DURING WARMUP OF THE LIQUID CONTENTS OF THE TUBE ANDDURING THE COAGULATION TESTS, THE INNER RADIUS OF THE TUBE PERMITTINGVERTICAL MANIPULATION OF A PROBE INTO AND OUT OF THE LIQUID SO AS TOSENSE A CLOT, THE TUBE TAPERING OUTWARDLY FROM THE CLOSED END TO THEOPEN END, THE TAPERING AND THE OUTER RADIUS OF THE TUBE BEING SELECTEDTO PROVIDE OPTIMUM CONTACT WITH THE HEAT SOURCE.